SUMMARY/ABSTRACT There is an urgent need to develop novel strategies for the treatment of drug-resistant hypertension (R-HTN) because it is the most important prognostic risk factor for cardiovascular and renal morbidity and mortality. Animal observations and the clinical trials have demonstrated that R-HTN is primarily neurogenic in origin, is characterized by increased sympathetic nerve activity (SNA). ACE2 has been identified in the brain cardiovascular regulatory areas (CVRRs). Overexpression of ACE2 in the brain CVRRs through viral vector injection or transgenic approach significantly attenuates hypersympathoexcitation and hypertension in hypertensive animals. However, the traditional brain injection method can?t been used in the humans due to the risk of brain infection. Thus, the major challenge for systemic agent delivery to the brain CVRRs is the blood- brain barrier (BBB). The transferrin (Tf) receptor are highly expressed on the surface of the brain blood vessel endothelial cells (the major component of the BBB). In the current study, PEGylated liposome will be surface- modified with the Tf-protein for specific targeting and conjugated to cell-penetrating peptide (CPP) in order to improve their transcytosis into the brain. Thus, we will design a lipid-based nanoparticles, Tf-CPP-liposome, for ACE2 gene-delivery across BBB to increase ACE2 brain expression. Furthermore, chitosan will be utilized to improve the ACE2 gene transferring by facilitating endosomal escape inside the cells. The central hypothesis is that ACE2 gene delivery into the brain CVRRs using BBB-penetrating Tf-CPP-liposome, a safe non-viral vector, through systemic administration, would increase ACE2 expression; attenuate hypertension in spontanesously hypertensive rats (SHR). This proposed research will develop a novel therapeutic tool to increase the brain expression of ACE2, the most powerful antihypertensive system in the central nervous system, through a unique Tf-CPP-liposome gene delivery system across the BBB. We predict that this novel therapeutic tool, combining the powerful target and the innovative delivery system, would be effective to treat neurogenic R-HTN, the major challenge for managing hypertension worldwide.